Funding:This work is supported by the Ministry of Science, ICT & Future Planning.The Korea multi-purpose accelerator complex (KOMAC) has two beam extraction points at 20 and 100 MeV for proton beam utilization. High availability should be achieved through high system reliability and short maintenance times to prevent and mitigate damage. A machine protection system is essential for avoiding damage leading to long maintenance times. KOMAC MPS that was developed using analog circuit interlock box has its limit to cover increasing interlock signals and modify interlock logic. The disadvantage has been solved with digital-based system for more efficient logic modification and interlock extension. The MPS is configured remotely using the EPICS-based application. In this paper, we present KOMAC machine protection architecture and performance results of the new machine protection system.

The IMP takes responsibility for the development of Injector II. The target energy index of it is 20-25Mev , which is an intense beam proton accelerator with high operation risk. In order to implement cutting the ion source beam in time when the beam position offset happened, the Injector II Machine Protection System is developed based on FPGA controller and PLC. This system aims to prevent device damage from continuous impact of intense beam, as well as obtains and stores status data of key devices when failures occur to implement failure location and analysis. The whole system is now operating stable in field, and the beam cutting time is less than 10us.

The European Spallation Source ERIC is being built in Lund, Sweden to complement the existing neutron sources in Europe and worldwide. ESS will be the bright-est neutron source ever built upon completion and aims to have an availability of 95% during steady state opera-tions. The purpose of Machine Protection at ESS is to protect the equipment in order to support the high availability. Due to the distributed nature of Machine Protection numerous design teams are involved to implement Protection Functions. The Machine Protection Development at ESS follows the Functional Protection lifecycle for System-of-systems developed at the facility. This paper focuses on the application of the Functional System Inter-action Process part of the Functional Protection method. To obtain the system interaction model, behavioural requirements and to allocate Protection Functions use case workshops are held. The feasibility of different system architectures and protection function implementations are discussed and simulated by going through fore-seen operational sequences, use cases. The different architectures and use cases are documented using Enter-prise Architect.

The reliable protection of the ESS equipment is important for the success of the project. This requires multiple systems and subsystems to perform the required protection functions that prevent undesired hazardous events. The complexity of the machine, the different technical challenges and the intrinsic organisational difficulties for an in-kind project like ESS impose serious challenges to the distributed Machine Protection strategy. In this contribution, the difficulties and adopted solutions are described to exemplify the technical challenges encountered in the process.